P641: REAL-WORLD DURATION OF VENETOCLAX TREATMENT FOR CHRONIC LYMPHOCYTIC LEUKEMIA AND SMALL LYMPHOCYTIC LYMPHOMA
Authors: Anna Teschemaker, Shweta Hakre, Jenny Tse, Nazneen Fatima Shaikh, Yifan Gu, Aimee Near
Journal: HemaSphere (2023)

Background: Venetoclax (V) is an approved fixed-duration treatment for chronic lymphocytic leukemia and small lymphocytic lymphoma (CLL/SLL), either as a 12-cycle regimen (~12 months) in combination with obinutuzumab (O) in the first-line (1L) setting or as a 24-cycle regimen (~24 months) in combination with rituximab (R) in the relapsed/refractory (R/R) setting. Aims: To analyze real-world treatment patterns of V+O in 1L and V+R in R/R settings in patients with CLL/SLL in the United States. Methods: A retrospective cohort analysis was conducted using the IQVIA PharMetrics® Plus database to identify patients aged ≥18 years treated with V+O (1L cohort; May 2019 to September 2021) or V+R (R/R cohort; June 2018 to September 2021). The start of the treatment regimen was defined as the index date. All patients were required to have ≥1 diagnosis code for CLL/SLL, 12 months of continuous enrollment (CE) prior to the index date, and ≥3 months of CE after the index date. Duration of treatment (DoT) was defined as time from index date to the earliest of either treatment discontinuation (defined as a ≥60-day gap in V prescription refills) or censoring (defined as end of follow-up). Fixed-duration treatment cycle was defined as 12- or 24-cycle dosing, corresponding to days 336−364 for the 1L setting and days 707−735 for the R/R setting, based on the dosing schedule plus 28 days. Kaplan-Meier analysis was used to estimate the probability of remaining on treatment for the 1L and R/R cohorts. Results: A total of 116 patients in 1L setting (mean age, 62.3 years; 73.3% male) and 145 patients in R/R setting (mean age, 64.2 years; 73.8% male) were identified; 48.3% of patients in the R/R cohort had prior targeted therapy. The median (95% CI) DoT in patients treated with V+O (n=115) was 12.4 (11.5, 13.4) months over a median follow-up of 11.4 months; the probability of remaining on treatment at 12, 18, and 24 months was 56.4%, 20.2%, and 5.1%, respectively. The median (95% CI) DoT in patients treated with V+R (n=133) was 24.5 (13.4−25.2) months over a median follow-up of 15.5 months; the probability of remaining on treatment at 24, 30, and 36 months was 53.8%, 19.0%, and 19.0%, respectively. Among patients treated with V+O, 47.8% (55/115) of patients had ≥12 months of follow-up, of whom 9.1% had fixed cycles and 38.2% discontinued early (median DoT: 4.6 months). Among patients treated with V+R, 29.3% (39/133) of patients had ≥24 months of follow-up, of whom 5.1% had fixed cycles and 46.2% discontinued early (median DoT: 7.1 months). The remaining patients in each cohort had DoT >12 or 24 cycles (Table). Summary/Conclusion: While the median DoT was approximately 12 months for patients treated with V+O and 24 months for patients treated with V+R in the 1L and R/R settings, respectively, a high number of patients did not maintain the fixed-dosing schedule. This study provides evidence that a V-based approach may not be suitable for all patients with CLL/SLL. Future studies should include additional follow-up with a larger sample, reasons for treatment discontinuation, and patient molecular genetic profile.Keywords: Venetoclax, Chronic lymphocytic leukemia, Real world data